Rapid Assessment Reference Condition Model
The Rapid Assessment is a component of the LANDFIRE project. Reference condition models for the Rapid Assessment were
created through a series of expert workshops and a peer-review process in 2004 and 2005. For more information, please visit
www.landfire.gov. Please direct questions to helpdesk@landfire.gov.
Potential Natural Vegetation Group (PNVG)
R9LLSH
Longleaf Pine - Sandhills
General Information
Contributors (additional contributors may be listed under "Model Evolution and Comments")
Modelers
Reviewers
Calvin Bailey
Kevin Hiers
cbailey@forestry.state.sc.us
khiers@tnc.org
Vegetation Type
Woodland
Dominant Species*
PIPA2
QULA
QUIN
QUMA
QUHE
QUGE
QUMA
Jim Murrian
General Model Sources
Literature
Local Data
Expert Estimate
LANDFIRE Mapping Zones
46
55
58
jmurrian@tnc.org
Rapid AssessmentModel Zones
California
Great Basin
Great Lakes
Northeast
Northern Plains
N-Cent.Rockies
Pacific Northwest
South Central
Southeast
S. Appalachians
Southwest
Geographic Range
This PNVG occurs from southeastern Virginia to east Texas, and south to central Florida.
Biophysical Site Description
Longleaf pine sandhills occur as dry woodlands/savannas on excessively drained or other xeric soils. Soils
are generally deep coarse sands or coarse sands underlain by clay, occasionally with dense surficial clay or
sandstone at the surface. It occurs on upland sites ranging from gently rolling, broad ridge tops to steeper
side slopes, as well as locally in mesic swales and terraces.
Vegetation Description
The canopy is strongly dominated by longleaf pine (Pinus palustris). Xerophytic scrub oaks, usually turkey
oak (Quercus laevis), sometimes mixed with blackjack oak (Quercus marilandica), laurel oak (Quercus
hemisphaerica), sand live oak (Quercus geminata), bluejack oak (Quercus incana), or sand post oak
(Quercus margaretta), are present as sparsely scattered midstory individuals or clumps and shrub-size firesprouts under the reference condition. The oaks become denser with fire exclusion. Other less xerophytic
oaks are absent or extremely rare.
The ground cover is dominated by wiregrass (Aristida stricta) over most of the range, but by bluestems
(Schizachyrium spp. or Andropogon spp.) in places where Aristida stricta is absent. The herb layer is
moderately dense, with a variety of other xerophytic herbs present. Low shrubs are sparse in the reference
condition, but can become dense with fire exclusion.
Canopy trees are patchy in distribution, with regeneration in canopy gaps of ¼ acre or less in size, midsuccessional clumps in similar sized patches, and the oldest trees occurring as isolated individuals. The
reference condition classes are aggregates of numerous patches well dispersed over the landscape. Canopy
gaps are created by fire mortality, lightning, and wind throw at the scale of individual trees or several trees.
Because of the irregular seed production of longleaf pine, canopy gaps may lack regeneration for several
*Dominant Species are from the NRCS PLANTS database. To check a species
code, please visit http://plants.usda.gov.
Final Document 9-30-2005
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years.
Disturbance Description
Longleaf pine sandhills were classified as Fire Regime Group I with frequent surface fires, every 2-5 years,
that generally burn across large expanses. Fires are usually low in intensity overall, but will occasionally kill
young regeneration patches and rarely kill individual older trees.
Adjacency or Identification Concerns
This PNVG is distinguished from other longleaf pine-dominated groups by the presence of xerophytic oaks
and the absence of other oaks, and by the absence of mesophytic or wetland herbs.
Longleaf pine sandhills are abundant in the Sandhills Region of North and South Carolina, and scattered on
relict beach ridge systems of the outer coastal plain and on sand dune systems associated with rivers. Rare
extreme sandhills (sand barrens) are so excessively drained that all strata are low in density, leaving much
bare sand even in the absence of fire. Fuels are too discontinuous to support regular fire. This model does
not cover these extreme communities.
Uncharacteristic vegetation types include even-aged canopy stands in which age structure has been
homogenized by logging or clearing. Examples include where loblolly or slash pine have replaced some or
all of the longleaf pine, where midstory oaks and/or low shrubs have become dense due to inadequate
burning, and where the grass-dominated ground cover has been lost due to soil disturbance or past canopy
closure.
Local Data
Expert Estimate
Literature
Sources of Scale Data
Scale Description
The landscape is adequate in size to contain the natural variation in vegetation and disturbance regimes.
Topographically, areas could be very large and extend continuously over a large expanse of the landscape,
or occur as small patches.
Issues/Problems
This model includes areas with Aristida stricta, Aristida beyrichiana and bluestems dominating the
understory. This fall line sandhill ecosystem may have two distinct xeric communities in the landscape.
Longleaf pine-scrub oak sandhills and longleaf pine-turkey oak sandhills can make up this PNVG within its
geographic range. Also, no insect and disease disturbances were noted during the succession pathway of
this PNVG. It was suggested that some level of disturbance from a bark beetle infestation be added to this
pathway. Most likely Classes B and D would be where the problem would occur. This addition has not been
done.
Model Evolution and Comments
The information from FRCC model with PNVG Code LLSH modeled by Mike Schafale on 03 June 2004
was used to load the Reference Condition Model Tracker Database.
*Dominant Species are from the NRCS PLANTS database. To check a species
code, please visit http://plants.usda.gov.
Final Document 9-30-2005
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Succession Classes**
Succession classes are the equivalent of "Vegetation Fuel Classes" as defined in the Interagency FRCC Guidebook (www.frcc.gov).
Class A
15 %
Early1 All Struct
Description
Class A is characterized by canopy
gaps, most single tree to a quarter
acre size, with pine regeneration up
to 15 years old, or lacking pine
regeneration because no mast year
has occurred since the gap opened.
The native grassy ground cover is
dominated by Aristida stricta. Tree
cover ranges from 0 to 50%.
Class B
6%
Mid1 Closed
Description
Class B includes patches, mostly ¼
acre or less in size, with canopy
pines 15-75 years old. A
substantial component of mid-story
hardwoods or shrubs is
encroaching in the absence of fire.
The hardwood/shrub cover is
greater than 50%. Canopy pine
cover ranges between 25-75%.
Class C
35 %
Mid2 Open
Description
Class C includes patches, most ¼
acre or less in size, with canopy
pines 15-75 years old. There is a
minimal hardwood component and
only sparse shrubs due to frequent
fire. Aristida stricta dominates the
ground cover. Canopy pine cover
ranges between 25-75%.
Dominant Species* and
Canopy Position
PIPA2 All
ARST5 All
Structure Data (for upper layer lifeform)
Cover
Height
Min
0%
Shrub Medium 1.0-2.9m
Tree Size Class
Upper Layer Lifeform
Herbaceous
Shrub
Tree
Fuel Model
Upper
Middle
Middle
Lower
Upper Layer Lifeform
Herbaceous
Shrub
Tree
Fuel Model
Upper
Middle
Middle
Lower
Upper Layer Lifeform
Herbaceous
Shrub
Tree
Fuel Model
Upper layer lifeform differs from dominant lifeform.
Height and cover of dominant lifeform are:
Structure Data (for upper layer lifeform)
Min
75 %
Cover
Height
Max
100 %
Tree Regen <5m
Tree Size Class
Tree Medium 10-24m
Medium 9-21"DBH
Upper layer lifeform differs from dominant lifeform.
Height and cover of dominant lifeform are:
6
Dominant Species* and
Canopy Position
PIPA2
QUMA
QULA2
ARST5
Tree Regen <5m
Sapling >4.5ft; <5"DBH
2
Dominant Species* and
Canopy Position
PIPA2
QUMA
QULA2
ARST5
Max
100 %
Structure Data (for upper layer lifeform)
Min
25 %
Cover
Height
Tree Regen <5m
Tree Size Class
Max
75 %
Tree Medium 10-24m
Medium 9-21"DBH
Upper layer lifeform differs from dominant lifeform.
Height and cover of dominant lifeform are:
6
*Dominant Species are from the NRCS PLANTS database. To check a species
code, please visit http://plants.usda.gov.
Final Document 9-30-2005
Page 3 of 6
Class D
40 %
Dominant Species* and
Canopy Position
PIPA2 Upper
QUMA Middle
Description
QULA2 Middle
Class D is characterized by
patches, most ¼ acre or less in size, ARST5 Lower
with canopy pines 75 or more years Upper Layer Lifeform
old. There is a minimal hardwood
Herbaceous
component and only sparse shrubs
Shrub
due to frequent fire. Aristida stricta
Tree
dominates the ground cover.
Fuel Model 2
Canopy pine cover ranges between
25-75%.
Late1 Open
Class E
4%
Late1 Closed
Description
Class E includes patches with
canopy pines 75 or more years old,
with a substantial component of
hardwoods and/or shrubs in either
the overstory or understory. The
ground cover is shrubby or sparse.
The hardwood/shrub cover is
greater than 50%.
Dominant Species* and
Canopy Position
PIPA2
QUMA
QULA2
ARST5
Upper
Middle
Middle
Lower
Structure Data (for upper layer lifeform)
Height
Max
75 %
Tree Regen <5m
Tree Size Class
Tree Medium 10-24m
Large 21-33"DBH
Upper layer lifeform differs from dominant lifeform.
Height and cover of dominant lifeform are:
Structure Data (for upper layer lifeform)
Cover
Height
Min
75 %
Max
100 %
Tree Regen <5m
Tree Size Class
Upper Layer Lifeform
Tree Tall 25-49m
Large 21-33"DBH
Upper layer lifeform differs from dominant lifeform.
Height and cover of dominant lifeform are:
Herbaceous
Shrub
Tree
Fuel Model
Min
25 %
Cover
9
Disturbances
Disturbances Modeled
Fire
Insects/Disease
Wind/Weather/Stress
Native Grazing
Competition
Other:
Other
Historical Fire Size (acres)
Avg: 10000
Min: 1
Max: 100000
Sources of Fire Regime Data
Literature
Local Data
Expert Estimate
Fire Regime Group: 1
I: 0-35 year frequency, low and mixed severity
II: 0-35 year frequency, replacement severity
III: 35-200 year frequency, low and mixed severity
IV: 35-200 year frequency, replacement severity
V: 200+ year frequency, replacement severity
Fire Intervals (FI)
Fire interval is expressed in years for each fire severity class and for all types of
fire combined (All Fires). Average FI is central tendency modeled. Minimum and
maximum show the relative range of fire intervals, if known. Probability is the
inverse of fire interval in years and is used in reference condition modeling.
Percent of all fires is the percent of all fires in that severity class. All values are
estimates and not precise.
Avg FI
Replacement
Mixed
Surface
All Fires
Min FI
130
1430
4
4
Max FI
Probability
25
500
1
10
0.00769
0.0007
0.25
0.25839
Percent of All Fires
3
0
97
References
Boyer, W.D. 1993. Long-term development of regeneration under pine seed tree and
shelter wood stands. Southern Journal of Applied Forestry 17: 10-15.
*Dominant Species are from the NRCS PLANTS database. To check a species
code, please visit http://plants.usda.gov.
Final Document 9-30-2005
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Brewer, J.S. and Platt, W.J. 1994a. Effects of fire season and herbivory on reproductive
success in a clonal forb, Pityopsis graminifolia. Journal of Ecology 82:665-675.
Brewer, J.S. and Platt, W.J. 1994b. Effects of fire season and soil fertility on clonal growth in
the pyrophilic forb, Pityopsis graminifolia (Asteraceae). American Journal of Botany 81:805814.
Brown, James K., Smith, Jane Kapler, eds. 2000. Wildland fire in ecosystems: effects of fire on flora. Gen.
Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky
Mountain Research Station. 257 p.
Christensen, N.L. 1981. Fire regimes in southeastern ecosystems. In Mooney, H.A., Bonnickson, T.M.,
Christensen, N.L., Lotan, J.E. and Reiners, W.A., eds. Fire regimes and ecosystem properties. USDA Forest
Service General Technical Report WO-26. pp. 112-136.
Croker, T.C., and Boyer, W.D. 1984 . Regenerating longleaf pine naturally. USDA Forest
Service Research Paper SE-105.
Frost, Cecil C. 1993. Four centuries of changing landscape patterns in the longleaf pine
ecosystem. In Hermann, S.M., ed. The longleaf pine ecosystem: ecology, restoration and management. Proc.
Tall Timbers Fire Ecol. Conf. No. 18. pp. 17-43.
Frost, Cecil C. 1997. Presettlement vegetation and fire history of the Savannah River Site and
vicinity, South Carolina. Savannah River Forest Station (map and text). U.S. Department of
Energy. 186 pp. [with 2 GIS maps].
Glitzenstein, J.S., Harcombe, P.A., and Streng, D.R. 1986. Disturbance, succession, and
maintenance of species diversity in an east Texas forest. Ecological Monographs 56:243258.
Hainds, M.J., Mitchell, R.J., Palik, B.J. and Boring, L.R. 1999. Abundance and distribution of
native legumes (Leguminosae) in frequently burned longleaf pine (Pinaceae)—wiregrass
(Poaceae) ecosystems. American Journal of Botany 86:1606-1614.
Hermann, S.M., Van Hook, T., Flowers, R.W., Brennan, L.A., Glizenstein, J.S., Streng, D.R.,
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North American Wildland and Natural Resource Conference 63:384-401.
Hiers, J.K., Wyatt, R., Mitchell, R.J. 2000. The effects of fire regime on legume reproduction in longleaf pine
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population dynamics of Schwalbea americana L. Plant Ecology 137:115-137.
Palik, B.J. and Engstrom, R.T. 1999. Species composition. In M.L. Hunter, Jr., ed. Maintaining biodiversity
in forest ecosystems. Cambridge University Press. Pp. 65-94.
*Dominant Species are from the NRCS PLANTS database. To check a species
code, please visit http://plants.usda.gov.
Final Document 9-30-2005
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Palik, B.J., Mitchell, R.J., Houseal, G. and Pederson, N. 1997. Effects of canopy structure on
resource availability and seedling responses in a longleaf pine ecosystem. Canadian Journal of Forest
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Platt, W.J., Evans, G.W. and Davis, M.M. 1988. Effects of fire season on flowering of forbs and shrubs in
longleaf pine forests. Oecologia 76: 353-363.
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*Dominant Species are from the NRCS PLANTS database. To check a species
code, please visit http://plants.usda.gov.
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